It was discovered that Squid incorrectly handled certain malformed packets received on the HTCP port. A remote attacker could exploit this with a specially-crafted packet and cause Squid to crash, resulting in a denial of service.
The problem can be corrected by updating your system to the following package versions:
24 February 2010
A security issue affects these releases of Ubuntu and its derivatives:
It was discovered that Squid incorrectly handled certain malformed packets received on the HTCP port. A remote attacker could exploit this with a specially-crafted packet and cause Squid to crash, resulting in a denial of service.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system upgrade is sufficient to effect the necessary changes.